Recently, display devices such as liquid crystal displays, electroluminescent displays, and plasma display panels, and the like, have been widely used due to inherent advantages thereof, such as rapid response speeds, low power consumption, and excellent color reproduction characteristics. Such display devices have been used in various electronic products such as televisions, computer monitors, notebook computers, mobile phones, refrigerator display units, personal digital assistants, automated teller machines, and the like. In general, such display devices include user interfaces using various input devices, for example, keyboards, computer mice, digitizers, and the like.
However, using a separate input device such as a keyboard, a mouse, or the like, may cause user inconvenience, in that users must learn the usage thereof, room therefor is required, and the like. Therefore, demand for an input device having a simplified structure and capable of reducing errors in an operation thereof while being conveniently used has increased. In accordance with such demand, a touchscreen with which a user may interact with a device through direct touch interaction, for example, direct contact between a screen and a user's fingers, a stylus, or the like, has been proposed.
In the case of a touchscreen, due to convenience in which a user may not only input information thereto without using a separate input device, but also rapidly and easily manipulate the touchscreen through icons displayed on the screen, touchscreen devices have been applied to various display apparatuses.
Meanwhile, in accordance with the recent trend for thinness in display devices, touchscreens are required to be thinned, and according to such a tendency, single-surface integrated touchscreens are under development.
FIG. 1 illustrates an example of a single-surface integrated touchscreen according to the related art. As illustrated in FIG. 1, the single-surface integrated touchscreen includes a substrate (not shown), a conductive pattern 20 formed on the substrate, an insulating layer 30 and a bridge electrode 40. Such a single-surface integrated touchscreen is generally manufactured through processes of forming a conductive pattern on a substrate, forming an insulating layer, and forming a bridge electrode.
On the other hand, the conductive patterns 20 are connected to one another in an x-axis direction, but are separated from one another in a y-axis direction. In addition, the bridge electrode 40 is provided to connect the separated y-axis conductive patterns to one another, and is generally formed using a conductive polymer, silver nanowire or the like. In this case, in order to separate the conductive patterns from the bridge electrode so as not to allow for the generation of conduction therebetween, the insulating layer 30 is formed between the conductive pattern and the bridge electrode.
Such a single-surface integrated touchscreen is generally manufactured through processes of forming a conductive pattern on a substrate, forming an insulating layer, and forming a bridge electrode. Here, the insulating layer 30 may be formed through a scheme in which an insulation composition is printed on a conductive pattern so as to have a predetermined pattern shape through a printing process using inkjet, screen, or the like.
However, in the case of using an insulation layer forming method according to the related art, a problem of a coffee ring phenomenon may be present, in which a height of an edge portion of an insulating layer is higher than that of a central portion thereof after a drying process due to a difference in an evaporation rate between the interior of a pattern and the exterior thereof at the time of curing the insulating layer. In the case of the occurrence of the coffee ring phenomenon, a bridge electrode may be cut or a connection state thereof may be deteriorated due to the occurrence of a relatively high level of step portion therein. In addition, in a case in which as the conductive pattern, a metal mesh is used, a phenomenon in which an ink composition flows along metal mesh pattern portions at the time of forming an insulation layer pattern may occur, such that it may be difficult to precisely form a pattern in a desired position. Furthermore, in this case, a problem in which a touch sensing function may be degraded due to the bridge electrode that is provided to connect y-axis conductive patterns to each other but that does not contact the conductive pattern, and the like, may occur.